Approximately 6 million Americans are allergic to cats, and although many persons allergic to cats do not have cats in their own homes, almost one third do. It has been suggested that 28% of homes in the United States have at least one cat (which equals at least 50 million cats). Patients allergic to cats often report a rapid onset of asthma and rhinitis upon entering a house with a cat. When tested, almost all of these patients will show a positive immediate hypersensitivity skin test to extracts of cat dander and will have serum IgE antibodies against cat allergens (Luczynska, JACI, August 1989.
To date, most treatments to cat sensitivity have centered around avoidance and immunotherapy. Avoidance can mean considerable alterations in ones living environment and daily routines. For example, to avoid excessive exposure to indoor allergens it is recommended that carpets be removed from floors, bedding be covered with special sheets, air conditioners be cleaned regularly, and air be filtered with costly air filters. The time, effort and expense often makes this type of treatment unappealing to allergy sufferers.
Immunization can be an effective treatment for allergies. Unfortunately, the expense of regular allergy shots, the time involved to receive treatment, and the variability of effectiveness are considerable deterrents for some patients. Furthermore, there is risk that a patient may have a severe reaction to the immunization and can even go into anaphylactic shock.